Solar sintering
Introduction
I
n a world increasingly concerned with questions of energy production and raw material
shortages, this project explores the potential of desert manufacturing, where energy and
material occur in abundance. In this experiment sunlight and sand are used as raw energy and
material to produce glass objects using a 3D printing process, that combines natural energy and
material with high-tech production technology. Solar-sintering aims to raise questions about the
future of manufacturing and triggers dreams of the full utilization of the production potential of
the world’s most efficient energy resource – the sun.
Whilst not providing definitive answers, this experiment aims to provide a point of departure
for fresh thinking.
In the deserts of the world two elements dominate – sun and sand. The former offers a vast
energy source of huge potential, the latter an almost unlimited supply of silica in the form of
quartz. Silica sand when heated to melting point and allowed to cool solidifies as glass.
This process of converting a powdery substance via a heating process into a solid form is
known as sintering and has in recent years become a central process in design prototyping
known as 3D printing.
These 3D printers use laser technology and solar technology to create very precise 3D objects
from a variety of powdered plastics, resins and metals – the objects being the exact physical
counterparts of the computer-drawn 3D designs inputted by the designer. By using the sun’s
rays instead of a laser and sand instead of resins, I had the basis of an entirely new solarpowered machine and production process for making glass objects that taps into the abundant
supplies of sun and sand to be found in the deserts of the world.
Project objectives
Our main goal is to deliver affordable, high quality "3d objects out of glass” by using the tow
available elements in desert (sand & sun).
Basic understanding of melting technology, creating 3D printing out of glass , self solar
powered and knowledge of industry economics is essential if the glass manufacturing process
is to be advanced to conserve energy, protect environmental quality, and secure capital
investment.
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This study unravels the complexities of the glassmaking process in all segments of the industry.
Solar powered Glass manufacturers, managers, administrators, scientists, engineers, and policy
makers will find this report a ready reference for further study.
Government agencies will understand how best to support glass manufacturing and apply
appropriate regulations to the industry.
Materials and equipment vendors can identify present and future needs to better serve glass
manufactures. Educators and students in higher education can profit from past research and
development to design pre-proprietary research.
Availability of solar energy in Jordan
 In Jordan there are 300 sunny days out of 365 days a year
 Average solar radiation is 2000 kilowatt hours per square meter per year
 Will be the inclusion of solar energy in the energy mix in Jordan through the construction
of plants for the generation of energy through photovoltaic cells capacity of 10 MW
 10% of Jordan's population uses solar heater for hot water

Solar cells will be used to generate electric power soon in Jordan
Silica sand in Jordan
Silica sand is defined as a high purity industrial mineral in which the sand grains are made
entirely of quartz. Impurities are very minor and commonly are clay minerals (kaolinite, illite),
iron oxides and heavy minerals. The term silica sand is applied to quartz sand that conforms to
the specifications of which the main composition is SiO2 > 99%, with very little contaminant
contents and heavy minerals of < 0.1% .The Government of Jordan has granted a concession to
the Jordan Mining Company to mine and export silica sand. The sand will be exported to
European countries. Amman Resources will build and operate a terminal in Port of Aqaba for
the receiving from trucks, storage and loading of the sand into ships.
The terminal will handle 1.5 million tons of sand initially, increasing to 3 million tons per year
in 2003. Materials Handling Consultants was assigned to develop and design the export
terminal, consisting of truck unloading facilities, storage shed (40,000 tons) with intake and
outtake conveyors and ship loader for ships up to 45,000 DWT .
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Location
White silica sand deposits are found exposed on the surface of Early Ordovician and Lower
Cretaceous sandstone in south of Jordan. Deposits are found in the following locations :
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Ras En Naqb area
Qa'Ed Disa area
Petra/ in El Biada area
Wade El Siq - Wade Rakia area
Al Jayoshia area
QUARTZ………………………………………………...................................................................................... 3
general description
Quartz is a hard mineral found in many types of rocks. Pure quartz, traditionally called rock
crystal, is colorless and transparent. As quartz crystals or rocks made from quartz break down,
they form silica sand. Quartz crystals and silica sand have very high melting points, and safety
precautions must be taken when melting the mineral at home. When exposed to extreme heat,
the quartz or silica sand creates molten glass, which can then be reshaped before it re-hardens
How to Melt Quartz
1-Arrange the quartz crystal or silica sand that you would like to melt on a fireproof surface,
such as cement or brick.
2-Put on the safety goggles and leather gloves. The goggles will protect your eyes from the
intense light, and the leather gloves will prevent your hands from getting burned.
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3-Use a lighter to light the torch. Turn the flame to the highest setting and the flame to the
quartz, moving it back and forth as necessary to reach the edges. Continue to heat the quartz
until it melts, at which point it will look like molten glass.
4- Repurpose the quartz by using small carbon rods to manipulate the melted quartz into your
desired shape. Allow the quartz to cool and you will now have a glass object.
What’s Quartz Glass?
Quartz glass is a kind of special glass which is made of single component-SiO2. Its series of
special performance that other material can’t replace, make quartz glass an indispensable
material in modern science and technology and modern industry.
Glass
Glass is older than recorded history, and yet it is as new as tomorrow! How, when, or where
man first learned to make glass is not known, but we do know that the ancient Egyptians
were making glass articles as early as 2,600 B.C.E. (The making of glass beads
may have
begun as much as 3000 years earlier.) They used it to make jewelry and luxury items, such as
decorative bowls and perfume bottles, available only to the wealthy.
Today, everyone uses glass. It is the stuff used to make jars, bottles, windows, light bulbs, and
any number of other everyday objects. But it is also the material used to make television tubes,
computer monitors, telescope lenses, spectrometer prisms, and all kinds of laboratory ware, as
well as the optical fibers that are revolutionizing modern communication. Glass has even
become a popular medium for artists, on a scale that is unprecedented.
Glass is really a physical state rather than a particular composition. It is a rigid material with the
extrinsic properties of a solid but with a less ordered structure, more similar to that found in a
liquid. When a liquid cools and hardens without forming crystals, it becomes a glass. For
example, when sugar is melted with other ingredients and then allowed to cool, it solidifies as
glassy “hard candies”. Many different substances can form glasses, but what most people have
in mind when they talk about glass is the stuff used to make
Windows and bottles, the common glassy material that is made from sand.
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SINTERING …………………………………….……………………..………………………………………………………………………..……..4
Definition
Sintering is a method used to create objects from powders. It is based on atomic diffusion.
Diffusion occurs in any material above absolute zero, but it occurs much faster at higher
temperatures. In most sintering processes, the powdered material is held in a mold and then
heated to a temperature below the melting point. The atoms in the powder particles diffuse
across the boundaries of the particles, fusing the particles together and creating one solid
piece. Because the sintering temperature does not have to reach the melting point of the
material, sintering is often chosen as the shaping process for materials with extremely high
melting points such as tungsten and molybdenum.
Sintering is traditionally used for manufacturing ceramic objects but finds applications in
almost all fields of industry. The study of sintering and of powder-related processes is known
as powder metallurgy. A simple, intuitive example of sintering can be observed when ice cubes
in a glass of water adhere to each other.
Densification of a polycrystalline objects close to, but below the melting point (Molten phases
may be present during the process.)
Shrinkage makes it difficult to prepare objects with a predefined shape and size.
If liquids are present they should be in minor amounts.
The verification range is the temperature interval between liquid formation and “slumping” due
to excess liquid. Should be as large as possible to avoid large shape changes.
Phase diagrams are important.
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sintering technologies
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Solar Sintering Project
4.3 sintering temperature
Sintering mechanisms
Sintering occurs by diffusion of atoms through the microstructure. This diffusion is caused by a
gradient of chemical potential – atoms move from an area of higher chemical potential to an
area of lower chemical potential. The different paths the atoms take to get from one spot to
another are the sintering mechanisms. The six common mechanisms are:
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Surface diffusion – Diffusion of atoms along the surface of a particle
Vapor transport – Evaporation of atoms which condense on a different surface
Lattice diffusion from surface – atoms from surface diffuse through lattice
Lattice diffusion from grain boundary – atom from grain boundary diffuses through
lattice
Grain boundary diffusion – atoms diffuse along grain boundary
Plastic deformation – dislocation motion causes flow of matter
Also one must distinguish between densifying and non-densifying mechanisms. 1–3 above are
non-densifying – they take atoms from the surface and rearrange them onto another surface
or part of the same surface. These mechanisms simply rearrange matter inside of porosity and
do not cause pores to shrink. Mechanisms 4–6 are densifying mechanisms – atoms are moved
from the bulk to the surface of pores thereby eliminating porosity and increasing the density
of the sample.
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3D PRINTING ……………………………………………………………………………………5
5.1 general description
3D printing is a phrase used to describe the process of creating three dimensional objects
from digital file using a materials printer, in a manner similar to printing images on paper. The
term is most closely associated with additive manufacturing technology, where an object is
created by laying down successive layers of material .Recently the term is increasingly being
used to describe all types of additive manufacturing processes, or even other types of rapid
prototyping technology.
Since 2003 there has been large growth in the sale of 3D printers. Additionally, the cost of 3D
printers has gone down.http://en.wikipedia.org/wiki/3D_printing - cite_note-1 The technology
also finds use in the fields of jewelry, footwear, industrial design, architecture, engineering and
construction
(AEC),
automotive,
aerospace, dental and medical industries,
education, geographic information systems, civil engineering, and many others.
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Solar Sintering Project
5.3 Applications
Hybrid solar-laser fascinating CNC machine design , build and operate to create 3D structures
of glass from sand and sand under the climate of Kingdom of Jordan The hybrid machile will be
fully powered from sun
The device consists of a large Fresnel lens that focuses the sun's rays to a focal point onto a
platform holding the silica sand. Two photovoltaic panels power a sun tracker that keeps the
focal point on target. When one layer is completed, the platform drops down to allow for the
sintering of the next layer, and so on until the object is completed.
Many traditional 3D printers use lasers to melt and soften materials, such as resin or plastic
powder, until the particles adhere to each other in a process known as sinteringas a result we
will use the sun's rays in place of a laser and silica sand in place of resin or plastic powder to
create 3D glass objects.
For the printer to work efficiently, the focal point of the lens would have to be trained right onto
the surface of the sand. As the sun would move and the focal point would shift during the
process, so he ordered a single 4.5-foot-wide lens and built a motorized frame for it. The
central sandbox, in which the objects are printed, shifts in all directions, and the entire
machine rotates around its center. Two aluminum arms, holding the lens at one end and solar
panels at the other, can pivot from straight overhead down to a 45-degree angle to chase the
sun. directed by a CAD design from a connected laptop, the printer uses the concentrated
beam of sunlight to slowly trace an object into the sandbox layer by layer. The sun melts the
sand, which cools into glass.
When the electronics began overheating, the soup can will be opened and cut , sliced and bent
its sides into fan blades, attached the creation to a spinning DC motor, and aimed it right at
the circuit board. The sun melted only the sand, and, after more than four hours, he printed a
glass bowl, and later several sculptures.
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Solar Sintering Project
METHODOLOGY………………………………………………………….…………………….6
Parts of solar sinter machine:
1 - a large Fresnel lens(48 inch×35 inch) .
2- CNC machine.
3- Light sensors (fixed tracker) .
4- Sand box (bed ) .
5- Two photovoltaic panels.
6- Solar-powered motor.
6.2 How it works
The Solar-Sinter machine is based on the mechanical principles of a 3D printer. A large Fresnel
lens (100 CM) diameter is positioned so that it faces the sun at all times via an electronic suntracking device, which moves the lens in vertical and horizontal direction and rotates the entire
machine about its base throughout the day. The lens is positioned with its focal point directed at
the centre of the machine and at the height of the top of the sand box where the objects will be
built up layer by layer. Stepper motors drive two aluminum frames that move the sand box in
the X and Y axes. Within the box is a platform that can move the vat of sand along the vertical
Z axis, lowering the box a set amount at the end of each layer cycle to allow fresh sand to be
loaded and leveled at the focal point.
Two photovoltaic panels provide electricity to charge a battery, which in turn drives the motors
and electronics of the machine. The photovoltaic panels also act as a counterweight for the lens
aided by additional weights made from bottles filled with sand.
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6.3 METHODOLOGY
Focal Point
This is the point which is get the foucus for the solar radiation on the bed of CNC machine to
start the sintering for the first layer After all the layers are done, we dig the object out of the
sandbox
Control Panel
We will control all the process by laptop which is work on (CAD CAM) program to control the
movement of the bed of CNC machine
Printing
 First put the designs of the object that we want to print in a CAd program.
 Consequentially, the computer will send the instructions to the printer, which works from
the bottom up.
 After a layer has cooled into glass, sand will be added to the sandbox in the center of the
machine and flattens it out, and the printer begins heating the next layer.
Power
Two photovoltaic panels, one on either side of the machine, keep the printer powered. since the
panels are attached to the same arms as the lens, they also benefit from the sun tracking, which
ensures that they always get direct light. The printer’s motors, the electronics, cameras and a
laptop all run on batteries charged by the solar panels
3D
with
:
printing process
sand and sunlight
The
an
and
machine is run off
electronic board
can be controlled
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using a keypad and an LCD screen. Computer drawn models of the objects to be produced are
inputted into the machine via an SD card. These files carry the code that directs the machine to
move the sand box along the X, Y coordinates at a carefully calibrated speed, whilst the lens
focuses a beam of light that produces temperatures between 1400°C and 1600°C, more than
enough to melt the sand. Over a number of hours, layer by layer, an object is built within the
confines of the sand box, only its uppermost layer visible at any one time. When the print is
completed the object is allowed to cool before being dug out of the sand box. The objects have
rough sandy reverse side whilst the top surface is hard glass. The exact color of the resulting
glass will depend on the composition of the sand, different deserts producing different results.
By mixing sands, combinatory colour and material qualities may be achieved.
3D printing out of glass – modified CNC Machine
LENS ……………………………………………………………………………………………7
Fresnel lens:
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Definition
The Fresnel lens reduces the amount of material required compared to a conventional
spherical lens by dividing the lens into a set of concentric annular sections known as "Fresnel
zones." In theory there are infinitely many such zones.
In the first (and largest) variations of the lens, each zone was actually a separate prism.
Though a Fresnel lens might appear like a single piece of glass, closer examination reveals that
it is many small pieces. 'Single-piece' Fresnel lenses were later produced, being used for
automobile headlamps, brake, parking, and turn signal lenses, and so on. In modern
times, computer-controlled milling equipment (CNC) might be used to manufacture more
complex lenses.
In each of these zones, the overall thickness of the lens is decreased, effectively dividing the
continuous surface of a standard lens into a set of surfaces of the same curvature, with
stepwise discontinuities between them. A Fresnel lens can be regarded as an array of prisms
arranged in a circular fashion, with steeper prisms on the edges and a nearly flat convex
center.
Fresnel lens design allows a substantial reduction in thickness (and thus mass and volume of
material), at the expense of reducing the imaging quality of the lens, which is why precise
imaging applications such as photography still use conventional bulky (non-Fresnel) lenses.
Fresnel lenses are usually made of glass or plastic; their size varies from large (old historical
lighthouses, meter size) to medium (book-reading aids, OHP viewgraph projectors) to small
(TLR/SLR camera screens, micro-optics). In many cases they are very thin and flat, almost
flexible, with thicknesses in the 1 to 5 mm (0.039 to 0.20 in) range.
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7.2 A plastic Fresnel lens
Since plastic Fresnel lenses can be made larger than glass lenses, as well as being much cheaper
and lighter, they are used to concentrate sunlight for heating in solar cookers, in solar forges,
and in solar collectors used to heat water for domestic use.
The ability of melting of the plastic Fresnel lenses was tested and evaluated on the following
object:
1. grid cooking
2. plastic tank
7.3 Uses
Solar power
grid cooking, melting metals( nickel, aluminum, steel), glass recycling, generating solar steam
and powering Stirling engines.
Also in the early 21st century, Fresnel reflectors began to be used in concentrating solar
power (CSP) plants to concentrate solar energy. One application was to preheat water at the
coal-fired Liddell Power Station, in Hunter Valley Australia.
Other application
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The use of Fresnel lenses for image projection reduces image quality,
Fresnel lenses have been used to increase the visual size of CRT displays in pocket televisions,
notably the SinclairTV80. They are also used in traffic lights. Fresnel lenses are also used to
correct several visual disorders, including several ocular-motility disorders such asstrabismus.
Perhaps the most widespread use of Fresnel lenses, for a time, occurred
inautomobile headlamps, where they can shape the roughly parallel beam from the parabolic
reflector to meet requirements for dipped and main-beam patterns, often both in the same
headlamp unit (such as the European H4 design). For reasons of cost, weight, and impact
resistance, newer cars have dispensed with glass Fresnel lenses, using multifaceted
reflectors with plain polycarbonate lenses. However, Fresnel lenses continue in wide used in
automobile tail, marker, and backup lights.
Fresnel lenses are also used in left-hand-drive European lorries entering the UK and Republic of
Ireland (and vice versa, right-hand-drive Irish and British trucks entering mainland Europe) to
overcome the blind spots caused by the driver operating the lorry while sitting on the "wrong"
side of the cab and driving on the "wrong" side of the road. They attach to the passenger-side
window.
Glass Fresnel lenses also are used in lighting instruments for theatre and motion pictures
New applications have appeared in solar energy, where Fresnel lenses can concentrate sunlight
(with a ratio of almost 500:1) onto solar cells. Thus the active solar-cell surface can be reduced
to a fraction compared to conventional solar modules. This offers a considerable cost-saving
potential by low material consumption, and it is possible to use high-quality and expensive solar
cells, which achieve a very high efficiency under concentration due to thermodynamic
effects.[14]
Fresnel reflectors are also currently being incorporated into next-generation solar thermalenergy systems
The Fresnel lens has seen applications for enhancing passenger reading lights on Airbus
aircraft: in a dark cabin, the focused beam of light does not dazzle neighboring passengers.
Fresnel lenses have also been used in the field of popular entertainment.
Projection
Fresnel lenses of different focal lengths (one collimator, and one collector) are used in
commercial and DIY projection. The collimator lens has the lower focal length and is placed
closer to the light source, and the collector lens, which focuses the light into the triplet lens, is
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placed after the projection image (an active matrix LCD panel in LCD projectors). Fresnel
lenses are also used as collimators in overhead projectors.
CALCALUTION ……………………………….8
Introduction:
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Figure6.1 : solar sinter method
The main technological parameters to control the solar sinter process are:
the pre-coated sand and its thermo-physical properties, such as density , specific heat cp, thermal
conductivity k, resin polymerization temperature range Tp, sand glass transition temperature Tg,
sand energy absorption a , reflection r and transmission coefficients , and other properties, such as
average grain dimension;
- The scan spacing;
- The solar beam power P;
- The solar spot diameter ;
- The scan speed V.
The four sand types under study, belonging to two categories (Table 6.1), are commonly used in
shell-moulding as they have a good compatibility to the fused metallic material.
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Table6. I Commercial sand properties
The last three process parameters determine the thermal radiant power density, that depends directly on
the solar power and inversely on the spot diameter and the scan speed; this latter has a direct impact on
productivity. On the other hand, the shell mechanical resistance is influenced by the depth p of the heat
affected zone (strictly related to the layer thickness in figure above) and by the temperature history
determined by the laser radiation, and finally by the process parameters.
In this particular solar sinter application, the solar beam raises the sand temperature allowing the
agglomeration of grains, without local burning. Under the thermal viewpoint, the phenomenon can be
schematically described as follows:
solar sinter is basically a heat transmission phenomenon in which the input energy, the solar radiation,
generates in the sand bed a mixed conduction and convection heat transfer. The grain agglomeration
strongly depends on the energy absorbed by the sand bed and on the energy required for the resin
polymerization, as well as on the chemical energy release during the heating process.
Solar sinter is a very dynamic process; hence its mathematical description involves the solution of the
unsteady heat conduction equation. In our model, as in the majority of those proposed in the literature,
the governing equation is the unsteady heat conduction equation. The resulting output data are:
- The temperature distribution and the maximum value on the surface Tmax;
- The depth p and the width of the heat-affected zone considered as the penetration of the isothermal
front corresponding to the resin glass-transition temperature.
Solar
radiation
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Reflection
Absorption
Transmission
Figure6. 2 : Energy flow in the solar sinter general process
When the laser spot hits the sand bed, the surface interaction with the radiant energy can be
described by the coefficients representing the fraction of absorbed a, reflected r, and
transmitted energy (Figure 2.) of course,
Equation 1
The three coefficients depend on the sand used, on the resin, and on the radiation itself, but they
are very difficult to obtain from the literature. For the pre-coated sands the absorptivity
coefficient a is sensibly higher than 0.9 and the reflectivity is lower than 0.01 .
6.1 The analytical solution of the 1D heat conduction equation:
A first method to model the SLS process is represented by the one-dimensional heat conduction
transfer equation. In this scheme, the heat transfer in a plane perpendicular to the laser radiation
incidence is neglected and the heat transfer by conduction is studied only in the direction of the
laser beam axis z; the material is considered as homogeneous. The phenomenon is governed by
the general one-dimensional heat conduction equation in unsteady (transient) conditions:
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Equation 2
With the following boundary conditions:
Where:
- h is the convective heat transfer coefficient between surface and surrounding air
(That can be conventionally assumed equal to 10 W/m2K for natural convection),
- is the specific thermal power of solar radiation (in W/m2),
ironmental temperature,
- t* is the radiation incidence duration.
A closed solution of the thermal conduction problem expressed by (2) can be obtained by
supposing that the thermal influenced zone, exposed since the time t = 0 to a heat flux , is small
with respect to the working area. Until t = t*, the temperature history during the radiation
incidence can be expressed as follows:
equation 3
Where ( = k / cp) is the sand thermal diffusivity, Ti the initial temperature of the sand
Bed and erfc is the complementary error function.
For t > t*:
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equation 4
Where Tf is the surface temperature at the end of the heating process and erfc is the error
Function.
To improve the one-dimensional schematization, it is possible to consider that the sand
temperature Ti in the (equation 3) is the environmental temperature at the initial step only. In
the next steps, it is necessary to take into account the effects connected with the solar incidence
in the adjacent region.
In order to consider the two-dimensional effects of the thermal heat conduction, a different
schematization of the solar incidence is then used: the well known «moving heat source». In
this way it is possible to evaluate the temperature field deformation, when the heat source
moves through the conductive medium, by adjusting the initial condition for the application of
(equation 3) and by evaluating the influence of the solar radiation in a plane perpendicular to
the z axis to estimate the width of the heat-affected zone also. With a heat source moving in the
x direction, the temperature history in the (x, y) plane can be expressed by:
Equation 5
Where '=P / p is the linear density of the heat flux expressed in W/m. The depth of the
Heat-affected zone p is adjusted in order to provide the same value of the maximum
Temperature obtained with the (equation3).
6.2 The numerical solution of the 3D heat conduction equation:
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To simulate in a more complete way the heat transmission related to solar sinter, it is necessary
to consider the three-dimensional heat conduction problem in a sufficiently large object, made
of homogeneous material, with the moving heat source boundary conditions .This problem is
not easy to solve and the hypothesis of a small thermal influenced zone with respect to the
working area cannot be removed. An alternative method consists in applying to a finite sand
bed volume the three-dimensional time dependent conduction problem expressed in the
classical form as:
Equation 6
that is valid for isotropic, heterogeneous media, where qv(x, y, z, t) is the heat generated per
unit of time and space, to be defined from the boundary conditions of the equation (2), and k,
and cp depend on space and time, for their dependence on the temperature. In this case the
radiation is considered as one-dimensional but the conduction within the sand is threedimensional.
Obviously an analytical solution of the (equation6) with this hypothesis is not currently
available but a solution based on numerical methods is possible, through the discretisation of
the spatial - by means of cubic cells – and of the temporal domains. The solution is a function
T(x, y, z, and t) and a finite domain is considered. An attempt to solve the three-dimensional
problem represented by the (equation6), transformed in the form of a transport equation for the
static enthalpy, has been made in this work by means of a commercial computational code,
FLUENT, with the SIMPLER algorithm .With this particular code, the sand porosity can also
be considered, by activating the porous media modeling option. The program flexibility allows
a complete schematization of the thermal phenomenon, including the influence produced by the
increase of temperature in the proximity of the radiation incidence point, and consequently it
allows a correct definition of the heat affected zone width, that cannot be considered directly in
the one-dimensional model. While the analytical solution of the (equation2) by means of the
(equations from 3 to 5) permits to investigate the influence of the solar power, the scan speed
and the spot diameter, with the three-dimensional schematization it is also possible to
investigate the influence of the scan spacing. But the modelisation of the moving heat source,
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representing the solar beam and its transformation in a time-dependent volumetric heat source,
is a very critical aspect, with the available options of the numerical code.
6.3 EXPERIMENTAL TESTS:
To calculate the sand thermo-physical properties and to determine the
actual heat amount absorbed by the sand bed.
The following thermo-physical sand properties have been determined in laboratory tests: the
specific heat, the thermal conductivity and the energy absorption during the heating process.
Table 6.2 Sand properties determined in laboratory tests
A specific analysis concerning the energy distribution within the sand, to obtain the terms (a)
and
of the (equation 1), has been carried on too. A schematization of the experimental
analysis is shown in (Figure 4). The values of the absorption and transmission coefficients have
been obtained with the following method:
- The nominal laser beam power is indicated on a power meter installed on the laser;
- The effective laser beam power on the sand bed has been measured with a power
Gauge, based on the thermal balance between incising and dispersed heat;
- The transmitted energy has been measured with the same power gauge, after its
Positioning under sand layers of different thickness (detail of Figure 4);
- The reflected energy r is lower than 1%.
The sand absorption coefficient (a) has been obtained with (equation1). Considering that only a
small amount of the energy is reflected and not more than 2-4% is transmitted at higher depth
than 0.2 mm, 95% of the radiant energy is absorbed by the sand finally, for the calculation:
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Solar radiation
6.4 calculation for time need to sinter sand:
: obtained from the figure below (in taffieleh, May) = 12
.
Area of lens = 48 inch ×35 inch = (48×0.0254) × (35×0.0254) = 1.0838688
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MEASUMENT AXILARY DEVICES
……………………………….9
1-thermopile
A thermopile is an electronic device that converts thermal energy into electrical energy. It is
composed of several thermocouples connected usually in series or, less commonly, in parallel.
Thermopiles do not respond to absolute temperature, but generate an
output voltage proportional to a local temperature difference or temperature gradient.
Thermopiles are used to provide an output in response to temperature as part of a
temperature measuring device, such as the infrared thermometers widely used by medical
professionals to measure body temperature. They are also used widely in heat flux
sensors (such as the Moll thermopile and Eppley pyrheliometer) and gas burner safety
controls. The output of a thermopile is usually in the range of tens or hundreds of millivolts. As
well as increasing the signal level, the device may be used to provide spatial temperature
averaging.
Thermopiles are also used to generate electrical energy from, for instance, heat from electrical
components. A pyrometer is a non-contacting device that intercepts and measures thermal
radiation, a process known as pyrometry. This device can be used to determine
the temperature of an object's surface.
2-pyrometer
A pyrometer is a non-contacting device that intercepts and measures thermal radiation, a
process known as pyrometry. This device can be used to determine the temperature of an
object's surface
EXPERIMENTS……………………………………………….……………………………….10
Osama farhat - Mutah University
Solar Sintering Project
1- On Silica sand
Ambient Temperature : 30 c
Sintering Temperature : 1600 c
Rate of solar radiation : 7.5 kw.h/.
"daily"
2. on recycling glass
Ambient Temperature : 25 c
Sintering Temperature : 1400- 1575 c
Rate of solar radiation : 5.5 kw.h/.
Osama farhat - Mutah University
"daily"
Solar Sintering Project
3. on plastic
Ambient Temperature : 25 c
Sintering Temperature : 1150- 260 c
Rate of solar radiation : 5.5 kw.h/.
"daily"
4. on steel
Ambient Temperature : 28 c
Sintering Temperature : 1500-1700 c
Rate of solar radiation : 7.0 kw.h/.
Osama farhat - Mutah University
"daily"
Solar Sintering Project
DISCUSION AND CONCLOSION……………………………….11
In our project we brought the Fresnel lens and we built the CNC machine then we did tests to
find if we can melt the sand, glass and plastic by our lens then we found that we could melt
the sand at 1600 c , the glass at 1500 c, the plastic between 115-260 c. above we have some
pictures that will show you what happened when we focus the solar radiation on plastic
gallon.
Osama farhat - Mutah University
Solar Sintering Project